/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_mat_scale_q15.c
*
* Description:	Multiplies a Q15 matrix by a scalar.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupMatrix
 */

/**
 * @addtogroup MatrixScale
 * @{
 */

/**
 * @brief Q15 matrix scaling.
 * @param[in]       *pSrc points to input matrix
 * @param[in]       scaleFract fractional portion of the scale factor
 * @param[in]       shift number of bits to shift the result by
 * @param[out]      *pDst points to output matrix structure
 * @return     		The function returns either
 * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
 *
 * @details
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.15 format.
 * These are multiplied to yield a 2.30 intermediate result and this is shifted with saturation to 1.15 format.
 */

arm_status arm_mat_scale_q15(
    const arm_matrix_instance_q15 *pSrc,
    q15_t scaleFract,
    int32_t shift,
    arm_matrix_instance_q15 *pDst)
{
    q15_t *pIn = pSrc->pData;                      /* input data matrix pointer */
    q15_t *pOut = pDst->pData;                     /* output data matrix pointer */
    uint32_t numSamples;                           /* total number of elements in the matrix */
    int32_t totShift = 15 - shift;                 /* total shift to apply after scaling */
    uint32_t blkCnt;                               /* loop counters */
    arm_status status;                             /* status of matrix scaling     */

#ifndef ARM_MATH_CM0_FAMILY

    q15_t in1, in2, in3, in4;
    q31_t out1, out2, out3, out4;
    q31_t inA1, inA2;

#endif //     #ifndef ARM_MATH_CM0_FAMILY

#ifdef ARM_MATH_MATRIX_CHECK
    /* Check for matrix mismatch */
    if((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols))
    {
        /* Set status as ARM_MATH_SIZE_MISMATCH */
        status = ARM_MATH_SIZE_MISMATCH;
    }
    else
#endif //    #ifdef ARM_MATH_MATRIX_CHECK
    {
        /* Total number of samples in the input matrix */
        numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;

#ifndef ARM_MATH_CM0_FAMILY

        /* Run the below code for Cortex-M4 and Cortex-M3 */
        /* Loop Unrolling */
        blkCnt = numSamples >> 2;

        /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
         ** a second loop below computes the remaining 1 to 3 samples. */
        while(blkCnt > 0u)
        {
            /* C(m,n) = A(m,n) * k */
            /* Scale, saturate and then store the results in the destination buffer. */
            /* Reading 2 inputs from memory */
            inA1 = _SIMD32_OFFSET(pIn);
            inA2 = _SIMD32_OFFSET(pIn + 2);

            /* C = A * scale */
            /* Scale the inputs and then store the 2 results in the destination buffer
             * in single cycle by packing the outputs */
            out1 = (q31_t) ((q15_t) (inA1 >> 16) * scaleFract);
            out2 = (q31_t) ((q15_t) inA1 * scaleFract);
            out3 = (q31_t) ((q15_t) (inA2 >> 16) * scaleFract);
            out4 = (q31_t) ((q15_t) inA2 * scaleFract);

            out1 = out1 >> totShift;
            inA1 = _SIMD32_OFFSET(pIn + 4);
            out2 = out2 >> totShift;
            inA2 = _SIMD32_OFFSET(pIn + 6);
            out3 = out3 >> totShift;
            out4 = out4 >> totShift;

            in1 = (q15_t) (__SSAT(out1, 16));
            in2 = (q15_t) (__SSAT(out2, 16));
            in3 = (q15_t) (__SSAT(out3, 16));
            in4 = (q15_t) (__SSAT(out4, 16));

            _SIMD32_OFFSET(pOut) = __PKHBT(in2, in1, 16);
            _SIMD32_OFFSET(pOut + 2) = __PKHBT(in4, in3, 16);

            /* update pointers to process next sampels */
            pIn += 4u;
            pOut += 4u;


            /* Decrement the numSamples loop counter */
            blkCnt--;
        }

        /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
         ** No loop unrolling is used. */
        blkCnt = numSamples % 0x4u;

#else

        /* Run the below code for Cortex-M0 */

        /* Initialize blkCnt with number of samples */
        blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

        while(blkCnt > 0u)
        {
            /* C(m,n) = A(m,n) * k */
            /* Scale, saturate and then store the results in the destination buffer. */
            *pOut++ =
                (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));

            /* Decrement the numSamples loop counter */
            blkCnt--;
        }
        /* Set status as ARM_MATH_SUCCESS */
        status = ARM_MATH_SUCCESS;
    }

    /* Return to application */
    return (status);
}

/**
 * @} end of MatrixScale group
 */
